B48 starting problems

1447 Views 20 Replies 5 Participants Last post by jlang, Nov 21, 2014

gzec

Discussion Starter · Nov 18, 2014

Weak start today on my 420. Wouldn't start in the yard. Just click. Where do I start? Battery shows 12.8 volts.

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Glenn,

Do you already have a starter improvement kit on this tractor? Has the ignition switch ever been replaced or is it original? Also, since it is a B Series engine with separate solenoid...it could be the solenoid is failing and needs to be replaced.

For hard starting issues ALWAYS start with cleaning the battery cable connections (lead oxide is nearly invisible and a good insulator, so scrape with a knife or use a very stiff wire brush...) Also, check the ground connections on the engine and frame for any voltage drop due to poor connection.

Chuck

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chuckv

· #4 · Nov 19, 2014

Glen,

If the key switch is original to the tractor I am sure that you should replace it...and clean the contacts of the mating connector, looking carefully for heat and corrosion damage. The B series solenoids are on the pedestal wall, and can be tested as seen here:

B-series solenoid test from 318 Tm1590.pdf (23.5 k)

Chuck

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chuckv

· #11 · Nov 20, 2014

Glenn,

I will ask a few more questions because I want to be sure I am not missing something here. You say that when you jump the starter the engine does not get cranked...but does the starter motor spin? Or, does it not turn at all but draw enough current to cause the sparking you noted?

In your post #543 above you mention that the battery measures 12.7 -- and I am sure that you meant Volts, not amps... Presumably this is when the starter is not being jumped. What is the battery voltage during the time the starter motor is powered during the jump? It should be well above 11 volts for a good battery, but under 10 volts during such a load would indicate that the battery is at its end of life, or at least not fully charged.

From all your descriptions, it sounds like the starter itself is in need of a rebuild, but you will have to take it out and to a shop to know for sure...

Chuck

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chuckv

· #19 · Nov 21, 2014

Yes -- stay away from the after-market starters from China...many posts here about how unsatisfactory they are compared to the original.

A good shop should be able to rebuild the one you have for about the same cost as those cheap imports that only last a season or less...

Chuck

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